1. Field of the Invention
The present invention relates to modular panels and apparatus for securing the panels to underlying structure, and more particularly to apparatus for securing, removing and accurately resecuring modular panels bearing fluid flow instrumentation or control mechanisms at the outer surface of a vehicle.
2. Description of the Related Art
In the art of fluid flow measurement, testing or control, there are many occasions in which it is desirable to secure instruments or control devices, such as probes, sensors, or other instrumentation, to a structure immersed in a fluid flow. Such instruments or control devices often are mounted on modular panels which cover, or hinder access to, equipment located within the structure and to which access is often necessary.
One type of modular panel which has proven very useful in controlling fluid flow over and around surfaces immersed in a variety of fluid environments, especially in the case of aircraft, automobile, or other vehicle surfaces, is the laminar flow control (LFC) panel.
Attachment of such panels via conventional fasteners has, so far, proven unacceptable. As has become well known in the art, modular LFC panels cannot be properly secured with conventional fasteners because such fasteners, when fully seated in the panel, fail to prevent the surface interruptions or discontinuities which result in undesired turbulence.
One such non-conventional fastener is known which can secure LFC panels to underlying supports while eliminating undesired turbulence. This fastener (disclosed in U.S. Pat. No. 5,261,759 to Decoux and assigned to the present assignee) includes a first, intermediate, flange portion for securing the LFC panel to an underlying support, and an end flange for engaging an outer surface of the LCF panel to seal regions within the panel from fluid flowing outside. When properly seated, surfaces of the fastener and the panel are flush with one another thereby eliminating turbulence.
Other fastening techniques for securing the panels which carry such instrumentation or control devices to a structure, such as a vehicle body, have included permanent bonding directly to the vehicle structure using epoxy adhesives, polysulfide or polyurethane bonding agents. Such panels essentially have to be destroyed in order to achieve removal of the panels from the vehicle structure.
Usually, the panels carrying the experimental instrumentation must be bonded over critical vehicle equipment. Failure in any region of attachment of the panels to the vehicle body would require cancellation of the experiment, a result which would prove extremely costly and time-consuming.
Moreover, when securing modular panels of this type on vehicle bodies, one concern is how rigidly the panels are maintained at their place of attachment. Another concern is how precisely the panels are located, or relocated after removal, over the region of the vehicle body to be covered.
It would therefore be desirable to have a fastening system which would enable quick and facile removal and reattachment of these modular panels to a vehicle body, and which would still prevent discontinuities at the surface of the modular panel immersed in the fluid flow.